Therapeutic electrode



July 31, 1923- 1,463,392

E. C. HANSON ET AL THERAPEUTIC ELECTRODE Filed Nov. 30, 1920 EARL (1. Hanson AND WENDELL L. CARLSON, OF WASHINGTON, DISTRICT OF COLUMBIA.

' THERAPEUTIC ELECTRODE.

Application filed November 30, 1920. Serial No. 427,439.

.7 0 all whom it may concern:

Be it known that we, EARL C. HANSON and WENDELL L. CARLSON, citizens of the United States, residing at Washington, District of Columbia, have invented (ertain new and useful Improvements in Therapeutic Electrodes, of which the following is a s cification. I ur invention relates to electrotherapeutic apparatus and more particularly to high frequency electrodes for electric treatment of the body.

The object of our invention is to provide a highfrequency eleztro-de of extremely simple construction not heretofore attained in the art.

Another object of the invention isto provide a high frequency electrode which is substantially non-destructible either physically or electrically.

A further object of our invention is to provide an electrode which has inherently a low'specific heat.

There'have been but few radical developments in the art of electrodes for electrotherapeutic purposes. We are familiar with previous constructions in which it was proposed to manufacture electrodes from wood, and from solid glass; In the case of solid glass electrodes, due to the relative high heat conductivity of the material, these electrodes conduct heat rapidly during the electrotheraeutic operation. Electrodes of this type come so hot that their satisfactory opera-' tion is enhanced. To obviate this difficulty,

electrodes wereconstructed of the vacuum type having a relatively thin glass walled envelope from which the air was exhausted. By a still later development the glass walled electrode was given an interior conductive coating and while it 'does notrequire the Vacuum heretofore employed, its construction is nevertheless breakable and conducwe have found that-bakelite will readily follow varlous shapes, according to the contour of. the body for which the instrument is intended.

Our invention may be more clearly-understood by reference to the accompanying drawings which form a part of this specification, in which,"

Figure 1 is a sectional view of one form of bakelite electrode;

Figure 2 is a sectional view of another form of bakelite electrode showing its assoclation in circuit with an electrotherapeutic apparatus, and;

Figure 3 shows a further construction of electrode partly in section.

Referring particularly to Figure 1 of the drawings, reference character 1 indicates a conductive plate electrically connected thru conducting rod 2 and screw threaded at 4. About this structure is molded a mass of bakelite 3 and shaped to conform With the contour of the body, the contour of the conductive members and bakelite molding depending upon the uses for which the instru-.

ment is intended. This bakelite construction is formed under high pressure and embeds the conducting parts throughout their area. The bakelite is molded over the electrically conducting surface 1, and forms a dielectric between i this surface and any grounded body to which the electrode is support 7.- 'This support is suitably slotted at 8 and the resilient portions brought together by adjustable thumb screw 9, which may also serve as a terminal connection from which a lead is taken to a source of high frequency oscillations.

Fi re 2 shows a different form of therapeutic electrode in which the mass of bakelite 3 is molded to conform with the con-- tour of conductive members 1 and 2 as indicated at surfaces 10 and 11. Thisdished form of electrode has many applicationsand is particularly illustrative" of the ir-' regular shapes in which bakelite .may be lations may comprise the thermionic vacuum tube apparatus 16 having its plate circuit energized by a generator 1? driven by motor 18. F or further details of this type electrotherapeutic apparatus reference is made to our Patent 1,338,812 granted May a, 1920.

Figure 3 shows another form of therapeutic electrode in which bakelite 15 is molded about the electrically conductive member 12. The electrical, conductive sur face 12 is connected through conducting rod 14 with terminal at of the electrode forming a connection for the high frequency apparatus.

This electrode is readily molded from bakelite and differs radically from the solid glass electrode, the vacuum electrodes and the glass Walled non-vacuum electrodes heretofore used, The fact that the electrode is non-breakable under impact to Which these instruments 7 are ordinarily subject, gives practically indefinite life to the device as compared to the relatively short life of the previous glass electrodes due to breakage The break down potential of balrelite is far in excess of voltages employed in electrotherapeutics and the material thus Withstands all potentials employed in this operation. The bakelite being a poor conductor of heat can therefore be used for theraface and a phenolic or cresylic condensation reeaeaa product molded about said surface and shaped to conform to the contour of various portions of the body.

3. An electrode of the class described comprising an electrically conducting surface and a coatingof a condensation product of a phenolic body and formaldehyde thereover.

4. An electrode for electrotherapeutics comprising an electrical discharge terminal and a dielectric'composition of aphenolic body and formaldehyde thereover.

5. An electrode of the class described comprising an electrically conducting surface formed to correspond with the contour of the body and a condensation product of a phenolic body and formaldehyde molded over said surface and correspondingly shaped in accord with the contour of the body.

6. An electrode of the class described comprising an electrical discharge terninal and adielectric material of a condensation product of a phenolic body and formalde hyde softened to surround said terminal and hardened under heat and great pressure to conform with the contour of the body for Which said electrode is intended.

7. An electrode of the class described comprising an'electrical discharge terminal and a dielectric composition of carbolic acid and formaldehyde molded thereover.

8. An electrode of the class described comprising an electrically conducting surface, a terminal rod connected thereto and a condensation-product of a phenolic body and formaldehyde molded about said conducting surface and terminal rod substantially embedding the entire area thereof and a connection at the end of said electrode whereby high frequency energy may be supplied to said conducting surface.

EARL C. HANSUN. l/VENDELL L. CARLSUN. 

